1. Field of the Invention
The invention is directed to an improved contact element holder for electrically contacting a rotor, and in particular on an improved brush holder for commutator or wiper ring machines.
2. Description of the Prior Art
Because of commutator nonconcentricities, commutator brushes of commutator machines, such as direct current small motors, cause abrupt changes at the transition from one commutator lamination to another, and similar noises that are transmitted via the brush carrier to the machine housing and are radiated from there. To reduce these running noises, noise-decoupled brush holders are used.
To assure good-quality commutation, it is important that the brush holder be located centrally to the commutator axis. Deviations from that cause asymmetries in the supply of electrical current, and the resultant forces are in turn the cause of noises. In the noise-decoupled brush holder, a certain flexibility of the brush quivers relative to the brush carrier must be accepted, and hence the inaccuracy, linked with this flexibility, of the central position of the commutator brushes makes the quality of commutation worse.
In a known noise-decoupled brush holder (German Patent Disclosure DE 42 41 405 A1), the decoupling elements between the carrier and the brush quiver are embodied as spring-elastic ribs, which connect an intermediate carrier, which firmly receives the brush quivers, to the carrier. Both the intermediate carrier and the carrier are embodied as plates that are located in the same plane. The ribs, embodied in meandering form, are either located in the plane of the plates or extend perpendicular to the plates; in the latter case, the meandering pattern points in the axial direction of the commutator. The two plates and the ribs are embodied as an integral injection-molded part.